Cat 249d hydraulic squeal

[Jeffcarvalho79]

Looking for any advice on where to look.

I have a Cat 249d track skid steer, when warm its making a high pitched hydraulic squeal, possibly a relief valve, never does it cold has to be between 165-170 hydraulic oil temp. Only does it on right side. No power loss or laziness. The machine doesn’t even have to move to make the noise barely touching the forward or reverse it makes the noise, so it’s not the brakes sticking or dragging. I have a video, just not sure how to upload to the forum.
Any help would be much appreciated.
Thanks
Jeff

 

[Nige]

I have a video, just not sure how to upload to the forum.

You need to host it somewhere like YouTube and then link it.

Either pull an oil sample and have it analyzed or pull the hydraulic return filter and take a close look at what’s in the bottom of the filter media pleats. My suspicion even before seeing the video is that you could have a drive motor on the way out.

 

[Jeffcarvalho79]

Video of problem

Dropbox

www.dropbox.com

 

[Jeffcarvalho79]

Dropbox

www.dropbox.com

 

[Jeffcarvalho79]

You need to host it somewhere like YouTube and then link it.

Either pull an oil sample and have it analyzed or pull the hydraulic return filter and take a close look at what’s in the bottom of the filter media pleats. My suspicion even before seeing the video is that you could have a drive motor on the way out.

I put Dropbox links, I don’t think it’s the drive motor and there is no change to the machine besides the noise, take a look at the videos if you don’t mind let me know what you think. Thank you.

 

[Nige]

From that video it’s difficult to tell. Maybe try putting the machine up on blocks so that you can run one side at a time and compare the difference.?

I would still be having an oil sample analysed if it was mine, just to see what’s in there.

Has the noise developed slowly I’ve time or did it appear suddenly.?

 

[Deimos]

Sounds very much like a bypass valve tripping. Could the hydraulic filter be clogged? Is the hydraulic oil of the proper quality? Has anyone accidentally added diesel fuel to the hydraulic tank?)))

 

[Jeffcarvalho79]

From that video it’s difficult to tell. Maybe try putting the machine up on blocks so that you can run one side at a time and compare the difference.?

I would still be having an oil sample analysed if it was mine, just to see what’s in there.

Has the noise developed slowly I’ve time or did it appear suddenly.?

It’s hard to say, I just use for personal use but heard it for the first time after using to take some trees out and the machine got an all day run. I can feel the squeal/vibration in the line.

 

[Jeffcarvalho79]

Sounds very much like a bypass valve tripping. Could the hydraulic filter be clogged? Is the hydraulic oil of the proper quality? Has anyone accidentally added diesel fuel to the hydraulic tank?)))

I leaned towards the bypass valve. I tried looking for an expanded view of the area on cat website but it wasn’t very detailed. Hydraulic oil looks brand new, filter looks good I change it not long ago. Yes oil is what it calls for. No diesel fuel in hydraulic tank it actually has a pad lock on it and I’m the only one who does the maintenance. I have it for personal use but used it to take some trees down and the machine got an all day run, it was at the end of the day that the noise started and I have only been able to replicate it when it runs for hours.

 

[Deimos]

Very often, unusual noises appear in the hydraulic system of various machines. This may not affect the machine's performance in any way, and it's not a malfunction. The only thing this noise can affect is your nerves. It's possible that when the hydraulics reach a certain temperature, a valve begins to throttle, producing a similar sound.
When I worked at a dealership, we had a problem with a noise coming from the pilot manifold on a wheeled excavator. The noise only bothered the operator, who was very nervous. But it didn't affect the machine's performance. Caterpillar sent us a valve with specially modified orifices, and the noise disappeared. But this was simply the operator's nitpicking, and the machine was under warranty. If the machine hadn't been under warranty, we would have told that operator to go to hell.

 

[Jeffcarvalho79]

Very often, unusual noises appear in the hydraulic system of various machines. This may not affect the machine's performance in any way, and it's not a malfunction. The only thing this noise can affect is your nerves. It's possible that when the hydraulics reach a certain temperature, a valve begins to throttle, producing a similar sound.
When I worked at a dealership, we had a problem with a noise coming from the pilot manifold on a wheeled excavator. The noise only bothered the operator, who was very nervous. But it didn't affect the machine's performance. Caterpillar sent us a valve with specially modified orifices, and the noise disappeared. But this was simply the operator's nitpicking, and the machine was under warranty. If the machine hadn't been under warranty, we would have told that operator to go to hell.

lol yea it’s just me being picky, but it’s only one side so I did worry a bit, even though it does not affect the machine at all, just me. Thank you for your response I got a good laugh.

 

[Deimos]

If you want to find and localize the source of a noise, you need a stethoscope. One person in the cabin should hold the levers to detect the noise, while the second should listen with a stethoscope to all suspect components. This is how we detected noise coming from the pressure-reducing pilot valve on a wheeled excavator.

 

[Nige]

lol yea it’s just me being picky, but it’s only one side so I did worry a bit, even though it does not affect the machine at all, just me.

I would still suggest an oil sample analysis to confirm or deny the presence of something that might be detrimental to the machine long-term. Last I heard the cost was around $35-40 from a Cat dealer for a package including the sample bottle kit, shipping, and analysis.

As a matter of interest what type/grade of oil are you using in the hydraulic system.?